What is Microgravity
Have you ever wondered what happens to astronauts when they experience little gravity in space? The term microgravity refers to - as stated in the name - “small gravity”. In a condition where all objects appear to be weightless, microgravity occurs. In space, true “zero gravity” doesn't exist, so equating microgravity with zero gravity is misleading. Gravity allows objects to attract each other, allowing the Moon to orbit the Earth and the Earth to orbit the Sun. However, what are the effects on the human body?
How does Microgravity affect Humans
Humans are constantly exposed to the force of gravity. However, scientists are still uncertain about the minimal level of gravity required to prevent any physiological changes. When people are exposed to the conditions of microgravity, it is typically expected that they will remain in those conditions for at least a year. Although we have very little understanding of what happens to humans’ bodies in space, we do know this: prolonged exposure can result in numerous long-term physiological effects, including cardiovascular deconditioning, loss of bone and muscle, as well as fluid shifts. Through multiple expeditions, NASA has concluded that an individual may lose anywhere from 1% to 1.5% mineral density per month in space, and unlike the loss of muscle mass (which also gets lost very rapidly during spaceflight), there may be no way to completely rehabilitate the body. However, additional studies have shown that there are much higher risks with living in a microgravity environment, including the shift of body fluids up to the head - pressuring the eyes and endangering one’s vision. If untreated, these risks can lead to severe dehydration and excessive calcium loss (calcium excretion), which can cause kidney stones to develop.
Current Treatment
Unfortunately, with little knowledge and understanding of microgravity’s effects on the human body, scientists must rely on estimates to aid in the development of protective measures against long-term consequences. Nevertheless, through numerous cognitive tests, as well as obtaining devices such as spinal ultrasounds or compression cuffs, space medicine is gradually advancing, and our understanding is slowly growing.
References
Wolfe, J. W., & Rummel, J. D. (1992). Long-term effects of microgravity and possible countermeasures. Advances in Space Research, 12(1), 281–284. https://doi.org/10.1016/0273-1177(92)90296-a
May, S. (2024b, February 8). What is microgravity? (Grades 5-8) - NASA. NASA. https://www.nasa.gov/learning-resources/for-kids-and-students/what-is-microgravity-grades-5-8/#:~:text=%E2%80%9CMicro%2D%E2%80%9D%20means%20%E2%80%9Cvery,Heavy%20objects%20move%20around%20easily.
Cranford, N. (2024b, April 16). The human body in space - NASA. NASA. https://www.nasa.gov/humans-in-space/the-human-body-in-space/
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